Compound for Forming Molybdenum-Containing Thin Film, Molybdenum-Containing Thin Film and Manufacturing Method Thereof

This application claims the priority of Korean Patent Application No. 10-0075060 filed on Jun. 10, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

The present disclosure relates to a compound for forming a molybdenum-containing thin film, a molybdenum-containing thin film, and a manufacturing method thereof, and more particularly, to a compound for forming a molybdenum-containing thin film with improved thermal stability and volatility, a molybdenum-containing thin film, and a manufacturing method thereof.

Molybdenum-containing thin films, such as a molybdenum metal thin film, a molybdenum oxide thin film, a molybdenum nitride thin film, a molybdenum sulfide thin film, and a molybdenum carbide thin film, can be used as diffusion barriers for metal wiring, gate lines, electrodes, and the like in semiconductor processes, and have been used variously as hard coating materials, sensors, channel layers, and catalysts in industry.

Molybdenum has a high work function due to a high melting point, low coefficient of thermal expansion, high heat transferability, and low resistance value, and has excellent thermal/chemical stability. Therefore, the molybdenum may be used as an important metal material capable of suppressing the leakage current of capacitors that require high dielectric constants in highly integrated DRAMs. In addition, the molybdenum has low resistance and may be replaced with tungsten (W) metal that has been currently used in a 3D NAND flash memory, or used as a diffusion barrier of tungsten (W) metal. Furthermore, the molybdenum may also be used as a seed layer for growth of the molybdenum, and a diffusion barrier in a metal process in non-memory fields such as logic devices.

Meanwhile, in the memory and non-memory fields, the development of products with high aspect ratios and complex shapes of three-dimensional structures has been diversified, and a molybdenum-containing thin film suitable for such products has been required.

However, conventional molybdenum precursors having a biscyclopentadienyl group and an imido group have poor vaporization characteristics, making it difficult to be used in a deposition process. In addition, conventional molybdenum precursors having an alkylcyclopentadienyl group, a nitrile group, and a carbonyl group include carbonyl groups, which are highly toxic and thus have a problem of being difficult to be applied to high-temperature processes, and have a low vapor pressure, making it difficult to handle, and also have a difficulty in forming high-quality thin films.

Accordingly, an object of the present disclosure is to provide a precursor for forming a molybdenum-containing thin film, which has no process and performance problems for application to next-generation semiconductor products, etc., has advantages in a process due to improved thermal stability, high volatility, and high vapor pressure, and can increase a deposition rate, a molybdenum-containing thin film manufactured using the precursor, and a manufacturing method thereof.

The objects of the present disclosure are not limited to the aforementioned objects, and other objects, which are not mentioned above, will be apparent to those skilled in the art from the following description.

A compound for forming a molybdenum-containing thin film according to an embodiment of the present disclosure is a compound represented by Chemical Formula 1, in which in Chemical Formula 1, Rand Rare each independently selected from hydrogen, a linear alkyl group having 1 to 6 carbon atoms, and a branched alkyl group having 3 to 6 carbon atoms, Ris selected from a linear alkyl group having 1 to 6 carbon atoms, a branched alkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 30 carbon atoms, and X is a halogen element.

A molybdenum-containing thin film according to an embodiment of the present disclosure is manufactured by depositing the compound represented by Chemical Formula 1.

A manufacturing method of a molybdenum-containing thin film according to an embodiment of the present disclosure includes depositing the compound represented by Chemical Formula 1 on a substrate.

Details of other embodiments will be included in the detailed description of the invention and the accompanying drawings.

According to an embodiment of the present disclosure, the precursor for forming the molybdenum-containing thin film includes an alkyl cyclopentadienyl group and a halogen element, and has excellent structural stability and thermal stability of the compound and high volatility, thereby easily forming a high-quality thin film.

The effects according to the present disclosure are not limited by the contents exemplified above, and more various effects are included in the present disclosure.

Advantages and features of the present disclosure, and methods for accomplishing the same will be more clearly understood from exemplary embodiments to be described below in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the following embodiments but may be implemented in various different forms. The embodiments are provided only to complete the disclosure of the present disclosure and to fully provide a person having ordinary skill in the art to which the present disclosure pertains with the category of the invention, and the present disclosure will be defined only by the appended claims.

In describing the present disclosure, a detailed description of related known technologies will be omitted if it is determined that they unnecessarily make the gist of the present disclosure unclear. The terms such as “including”, “having”, and “consisting of” used herein are generally intended to allow other components to be added unless the terms are used with the term “only”. When a component is expressed in a singular form, the singular form may include a plural form unless clearly stated otherwise.

Components are interpreted to include an ordinary error range even if not expressly stated.

A compound for forming a molybdenum-containing thin film according to an embodiment of the present disclosure may be represented by the following Chemical Formula 1. The compound represented by Chemical Formula 1 may be used as a precursor material for forming a molybdenum-containing thin film.

In Chemical Formula 1, Rand Rmay be each independently selected from hydrogen, a linear alkyl group having 1 to 6 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms.

In Chemical Formula 1, Rmay be selected from a linear alkyl group having 1 to 6 carbon atoms, a branched alkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 30 carbon atoms.

In this case, since the vapor pressure property is excellent, the supply and deposition of the compound is easy during a thin film formation process, and a polymer thin film having a high deposition rate may be formed.

For example, in Chemical Formula 1, Rmay be hydrogen, Rmay be a linear alkyl group having 1 to 6 carbon atoms, and Rmay be a branched alkyl group having 3 to 6 carbon atoms. In this case, since the vapor pressure property is excellent, the deposition process is easy, and the impurity content in the thin film is greatly reduced.

As another example, in Chemical Formula 1, Rand Rmay be linear alkyl groups having 1 to 6 carbon atoms, and Rmay be a branched alkyl group having 3 to 6 carbon atoms. At this time, Rand Rmay be different from each other. In this case, since the vapor pressure property is excellent, the deposition process is easy, and the impurity content in the thin film is greatly reduced, thereby forming a high-quality molybdenum-containing thin film.

In Chemical Formula 1, X may be a halogen element. Specifically, for example, in Chemical Formula 1, X may be a halogen element such as chlorine, bromine, or iodine. Preferably, for example, X may be chlorine. The bonding of Mo and halogen elements has a higher bonding energy than the bonding of Mo and carbon elements. Therefore, when the compound of Chemical Formula 1 including the Mo-halogen element bond is used as a precursor for forming a molybdenum-containing thin film, a high-quality molybdenum-containing thin film with excellent thermal stability and almost no impurities may be formed.

Specifically, for example, the compound for forming the molybdenum-containing thin film may be a compound represented by the following Chemical Formula 2 or 3. In this case, the thermal stability and volatility are excellent. Therefore, the compound may be used as a precursor material for forming the molybdenum-containing thin film to easily form a high-quality molybdenum-containing thin film.

The molybdenum-containing thin film may be formed by depositing the compound for forming the molybdenum-containing thin film described above. Hereinafter, a method for manufacturing a molybdenum-containing thin film on a substrate using the compound described above will be described in detail.

For example, the molybdenum-containing thin film may be formed by depositing a compound on a substrate by any one method of plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition, plasma-enhanced atomic layer deposition, and thermal atomic layer deposition.

Specifically, for example, the method for manufacturing the molybdenum-containing thin film includes a first step of cleaning and surface-treating a substrate, a second step of mounting the substrate in a chamber and heating the substrate, a third step of supplying a compound for forming the molybdenum-containing thin film represented by Chemical Formula 1 onto the substrate to form a single layer, a fourth step of supplying a reaction gas to the chamber to form a molybdenum thin film, and a fifth step of purging to remove an unreacted product.

The compound for forming the molybdenum-containing thin film represented by Chemical Formula 1 is the same as described above, and thus a duplicate description will be omitted.

First, the first step is a step of cleaning and surface-treating the substrate.

Before depositing the thin film, the substrate is cleaned to remove oil and water or foreign substances that may exist on the substrate. In addition, the substrate may be cleaned by selecting a dry or wet method, and both methods may also be used. For example, the cleaning may be performed using processes such as degreasing using an organic solvent, acid treatment, alkaline treatment, ultrasonic cleaning, and heat treatment, but is not limited thereto.

For example, a natural oxide film on the substrate surface may be removed using an etching solution such as hydrofluoric acid or sulfuric acid, or through other gaseous cleaning methods such as dry ice cleaning and UV ozone cleaning. In addition, in order to prevent the formation of the oxide film and facilitate the formation of the thin film, surface treatment may be performed to form a protective layer on the surface of the cleaned substrate.

Before mounting the cleaned and surface-treated substrate in the chamber, an inert gas may be purged inside the chamber to remove impurities. However, the present disclosure is not limited thereto. As such, a high-quality thin film may be formed by removing the impurities to suppress the generation of by-products due to side reactions. After removing impurities, the inside of the chamber may be maintained in a vacuum state for the reaction, but is not limited thereto.

The second step is a step of mounting the substrate in the chamber and heating the substrate. The heating temperature of the substrate in the second step may be 50° C. to 700° C. Preferably, the heating temperature of the substrate may be 250° C. to 400° C. or 250° C. to 350° C. In this case, the reaction may proceed quickly and smoothly, thereby forming a high-quality thin film.

The third step is a step of supplying the compound for forming the molybdenum-containing thin film represented by Chemical Formula 1 onto the substrate to form a single layer.

For example, the compound for forming the molybdenum-containing thin film may be supplied into the chamber by a bubbling method, but is not limited thereto. Optionally, the compound may be supplied together with a carrier gas as needed. The carrier gas may be used with gases that are not reactive with the compound and are lighter than the compound, so that the vaporized compound may be easily transferred to the reaction chamber. In addition, the reaction such as a growth rate of the thin film and the like may be easily controlled by controlling the flow rate of the compound to be supplied to the chamber. For example, the carrier gas may include one or more selected from argon (Ar), helium (He), and neon (Ne), but is not limited thereto.

The carrier gas may also be supplied into the chamber together with the compound by a bubbling method, but is not limited thereto.

As such, when the compound for forming the molybdenum-containing thin film is supplied onto the heated substrate, a single layer containing molybdenum is formed.

The fourth step is a step of forming the molybdenum thin film by supplying the reaction gas to the chamber.

The reaction gas reacts with the compound on the previously formed single layer to form a molybdenum-containing thin film. For example, the reaction gas may include at least one of O, O, HO, NO, NO, NO, HO, H, NH, alkylamine, hydrazine derivative, SiH, SiH, BH, BH, borane ammonia complex, GeH, and PH, but is not limited thereto.

For example, the molybdenum oxide thin film may be formed by supplying Oas the reaction gas, but is not limited thereto.

For example, the pressure inside the reactor may be maintained at 1×10Torr to 100×10Torr. Within this range, the reaction may proceed smoothly while ensuring the safety of the process.

The fifth step is a step of purging to remove the unreacted product. When a thin film with a desired thickness is formed, the inside of the chamber is purged to remove the unreacted product. For example, the chamber may be purged with inert gas such as argon (Ar), helium (He), and neon (Ne) to remove the unreacted product, but is not limited thereto.

Optionally, the method may further include a step of post-treating the thin film, if necessary. For example, the post-treating may be performed by any one method of an inductively coupled plasma (ICP) treatment process, a rapid thermal annealing (RTA) process, or a combination thereof, but is not limited thereto.

The method for manufacturing the molybdenum-containing thin film according to an embodiment of the present disclosure uses the compound represented by Chemical Formula 1 as a precursor, which has high thermal stability and excellent vapor pressure property. Accordingly, it is easy to control the supply and reactions of reactants in the deposition process, and a high-quality molybdenum-containing thin film with almost no impurities may be formed.

Therefore, the molybdenum-containing thin film may be used as wirings or electrodes of a semiconductor device, as well as electrodes or diffusion barriers of a memory device, thereby improving the performance of the device.

Hereinafter, the compound for forming the molybdenum-containing thin film according to the present disclosure and the molybdenum-containing thin film manufactured using the same will be described in more detail through the following Examples. However, these Examples are only presented to aid the understanding of the present disclosure, and the present disclosure is not limited to the following Examples.